The present invention relates to a high-pressure compressor of a compression type provided with a compression mechanism for compressing a sucked operating fluid to generate a high-pressure operating fluid, particularly to an improvement of a compression mechanism for reciprocating/driving a piston with respect to a cylinder by rotation of a motor.
For a high-pressure compressor of a compression type provided with a compression mechanism for reciprocating/driving a piston with respect to a cylinder by rotation of a motor and compressing an operating fluid sucked by the driving to generate a high-pressure operating fluid, as the invention by the present applicant, a multistage compression apparatus (hereinafter referred to the prior art) is disposed as one high-pressure gas compressor invented before the application date of the present application, for example, in Japanese Patent Application Laid-Open No. 81780/1999.
The prior art will be described hereinafter based on FIGS. 1 to 4. A multistage compression apparatus 100 constitutes a four-stage compressor provided with four compression sections (compression stages) 101, 102, 103, 104. The compression sections 101 and 103 are arranged on a horizontal axis 106, the compression sections 102 and 104 are arranged on a horizontal axis 105, and a reciprocating compression mechanism is constituted in which a piston as a movable member reciprocates/operates on these axes 106, 105 in a cylinder as a fixed member. Thereby, the operating fluid sucked via a suction pipe 118 is compressed in the first compression section 101, subsequently the operating fluid compressed in the first compression section 101 is passed via a pipeline 5 into the second compression section 102 and compressed, the operating fluid compressed in the second compression section 102 is passed via a pipeline 6 into the third compression section 103 and compressed, the operating fluid compressed in the third compression section 103 is passed via a pipeline 7 into the fourth compression section 104 and compressed, and the high-pressure operating fluid provided with a predetermined pressure and flow rate in this manner is discharged via a discharge pipe 8.
Examples of the operating fluid in the multistage compression apparatus 100 include nitrogen, natural gas, sulfur hexafluoride (SF6), air, and other so-called gases, and the multistage compression apparatus 100 is applied to a natural gas charging machine to a car bomb using a natural gas, high-pressure nitrogen gas supply to a gas injection molding machine using a high-pressure nitrogen gas during injection molding of synthetic resin, a charging machine of high-pressure air to an air bomb, and the like.
In the multistage compression apparatus 100, a piston 51 in the first compression section 101 and a piston 53 of the third compression section 103 are connected to a yoke 1A on the axis 106, and a cross slider 2A movably disposed to cross the axis 106 in the yoke 1A is connected to a crank shaft 4 via a crank pin 3. The axis 105 forms an angle of 90 degrees with the axis 106 in a vertical view. Moreover, a piston 52 of the second compression section 102 and a piston 54 of the fourth compression section 104 are connected to a yoke 1B on the axis 105, and a cross slider 2B movably disposed to cross the axis 105 in the yoke 1B is connected to the crank shaft 4 via the crank pin 3.
The crank shaft 4 is rotated by an electric motor (not shown) disposed below the compression sections 101 to 104, the crank pin 3 disposed on the crank shaft 4 in an eccentric manner is rotated around the crank shaft 4, with respect to the yoke 1A the cross slider 2A moves to handle displacement of the crank pin 3 in a direction of axis 105, the yoke 1A moves to handle the displacement of a direction of axis 106, and the pistons 51, 53 reciprocate only in the direction of the axis 106.
On the other hand, with respect to the yoke 1B, the cross slider 2B moves to handle the displacement of the crank pin 3 in the direction of axis 106, the yoke 1B moves to handle the displacement of the direction of axis 105, and the pistons 52, 54 then reciprocate only in the direction of the axis 105.
FIG. 4 is a sectional view showing a structure of the first compression section 101 of the multistage compression apparatus 100. The first compression section 101 is provided with a first compression chamber 58 and a second compression chamber 59 before and after the piston 51. When the piston 51 advances and valves a, b are closed, the operating fluid is sucked into the first compression chamber 58 via opened valves e, f from directions shown by arrows. Additionally, when the operating fluid of the second compression chamber 59 is compressed to reach a predetermined pressure, the fluid is discharged to the outside via opened valves c, d, and fed to the next second compression section 102 via the pipeline 5 as shown by an arrow.
Subsequently, when the piston 51 moves backward, the valves e, f are closed, the operating fluid in the first compression chamber 58 is compressed to reach the predetermined pressure and open the valves a, b, and the operating fluid is discharged to the second compression chamber 59. Numeral 60 denotes a rod guide for smoothly guiding a connecting rod 57 to a predetermined position so that no vibration occurs.
As described above, the first compression section 101 of the multistage compression apparatus 100 is a double compression mechanism (double action mechanism) structured to suck, compress and discharge the operating fluid in two stages in one cylinder 55. The second, third and fourth compression sections 102, 103, 104 do not comprise the double compression mechanism like the first compression section 101, and comprise a so-called single action mechanism constituted to perform a usual operation of compressing the gas sucked into the cylinder in one stage in the reciprocating motion of the piston with respect to the cylinder.
In the aforementioned constitution, a nitrogen gas as the operating fluid sucked via the suction pipe 118 indicates a pressure of about 0.05 MPa (G), and is compressed by the first compression section 101 until the pressure indicates about 0.5 MPa (G), and the compressed nitrogen gas is supplied to the second compression section 102 via the pipeline 5. The nitrogen gas is compressed to indicate about 2 MPa (G) in the second compression section 102, and the compressed nitrogen gas is supplied to the third compression section 103 via the pipeline 6. The nitrogen gas is compressed to indicate about 7 to 10 MPa (G) in the third compression section 103, and the compressed nitrogen gas is supplied to the fourth compression section 104 through the pipeline 7. In the fourth compression section 104, the high-pressure gas (high-pressure operating fluid) compressed to indicate about 20 to 30 MPa (G) is supplied to an accumulator via the discharge pipe 8, and the high-pressure nitrogen gas is supplied to a gas injection molding machine from the accumulator.
In the aforementioned prior art, as a first constitution, for the pistons 53, 54 of the third and fourth compression sections 103 and 104, as shown in FIG. 5 and FIG. 6 as an enlarged view of a circle P of FIG. 5, a plurality of labyrinth grooves 70 are formed in the peripheral surfaces of the pistons 53, 54, in the compression mechanism, a gap of 2 to 6 xcexcm (micrometers) is formed between the piston 53, 54 and a liner cylinder 73A, 74A disposed on the inner surface of the cylinder 73, 74, and the gas flowing through the gap flows into the labyrinth groove 70 and generates a turbulence for a gas sealing system to form a so-called non-lubricating labyrinth seal structure. Moreover, a tip end peripheral edge 75 of the piston 53, 54 is obliquely and linearly chamfered, so-called C-chamfered, and an open edge 76 of the labyrinth groove 70 is formed as a sharp edge.
Moreover, as a second constitution, as shown in FIG. 7, in the third and fourth compression sections 103, 104, in a top dead point in reciprocating/driving of the piston 53, 54, a rear end 78 of the piston 53, 54 is positioned inside the liner cylinder 73A, 74A by a length L1. Moreover, as shown in FIG. 8, in a lower dead point, a tip end 77 of the piston 53, 54 is positioned inside the liner cylinder 73A, 74A by a length L2. Specifically, the length L1, L2 indicates a friction distance when the piston 53, 54 is displaced with respect to the liner cylinder 73A, 74A.
Furthermore, as a third constitution, as shown in FIG. 9, in the second compression section 102, an aluminum cylinder 72 forms a uniform cylindrical inner surface 81 with the same inner diameter (diameter of 75 mm) toward a discharge plate 80, and the piston 52 reciprocates along the cylindrical inner surface 81. The piston 52 is provided with a plurality of PTFE piston rings 83 at intervals to seal with the cylinder 72. As shown in FIG. 10, a piston plate 84 is fixed to the tip end of the piston 52 to support the piston ring 83 on the tip end.
Additionally, as a fourth constitution, as shown in FIG. 11, in the third and fourth compression sections 103 and 104, the pistons 53, 54 are connected to the yokes 1A, 1B via connecting rods 85, 86, respectively, and reciprocate in the cylinders 73, 74 by rotation of the electric motor. In the connection of the piston 53 to the connecting rod 85, and the connection of the piston 54 to the connecting rod 86, male connectors 87, 88 extended from the pistons 53, 54 engage with female connectors 89, 90 formed in the connecting rods 85, 86 so that mutual rotation is possible. Numerals 91, 92 denote guide rings disposed on the connecting rods 85, 86, respectively. Numerals 79, 79A denote reinforcing materials embedded in the connecting rods 85, 86 in positions where the male connectors 87, 88 contact.
Moreover, as a fifth constitution, in the third and fourth compression sections 103 and 104, the pistons 53, 54 shown in FIG. 12 have flat surfaces on tip ends as shown in FIGS. 5 and 6. Furthermore, the respective tip end peripheral portions 75 are obliquely and linearly chamfered, so-called C-chamfered.
In the aforementioned prior art, in the first constitution shown in FIGS. 5 and 6, there is a problem that the inner surfaces of the cylinders 73, 74 are worn by the pistons 53, 54. Specifically, the piston 53, 54 is disposed in the horizontal direction, and is displaced downward by its weight by the gap between the piston 53, 54 and the liner cylinder 73A, 74A to contact the inner surface of the liner cylinder 73A, 74A before the compressor starts. When the compressor starts in this state, a phenomenon disadvantageously occurs in which the inner surface of the liner cylinder 73A, 74A is scraped by the tip end of the piston 53, 54 and the edge of the opening end of the labyrinth groove 70.
Moreover, in the aforementioned prior art, in the second constitution shown in FIGS. 7 and 8, there is a problem that the inner surfaces of the liner cylinders 73A, 74A are worn by the pistons 53, 54. Specifically, in the top and lower dead points of the pistons 53, 54, the ends 77, 78 of the pistons 53, 54 are positioned in the liner cylinders 73A, 74A by the lengths L1, L2. Therefore, in the downward displacement of the pistons 53, 54, the phenomenon occurs in which the tip and rear ends of the pistons 53, 54 scrape the inner surfaces of the liner cylinders 73A, 74A.
Furthermore, in the prior art, in the third constitution shown in FIGS. 9 and 10, since the inner surface of the cylinder 72 is a uniform cylindrical inner surface with the same inner diameter, in order to enlarge a removal capacity in a compression process, a cylinder inner diameter and a piston outer diameter have to be enlarged, and there is a problem that size enlargement necessarily results.
Additionally, in the prior art, in the fourth constitution shown in FIG. 11, the piston is connected to the connecting rod by the engaging connection of the male connector with the female connector, and there is a problem that a processing for accurately keeping a processing precision of the engaging connection portion is considerably laborious. Moreover, the reinforcing material is necessary for maintaining performance.
Moreover, in the fifth constitution in the prior art, there is a problem that the inner surfaces of the liner cylinders 73A, 74A are worn by the pistons 53, 54. Specifically, since the piston 53 (54) in FIG. 12 has the flat surface as the tip end surface, and the tip end peripheral edge 75 is C-chamfered, in the downward displacement of the pistons 53, 54 the phenomenon of scraping the inner surfaces of the liner cylinders 73A, 74A occurs, and there is also a problem that a top clearance increases.
In consideration of the aforementioned problems, an object of the present invention is to provide a compression apparatus of a compression system high-pressure compressor in which wear of a cylinder inner surface as in the prior art is prevented, removal capacity is increased, processing is facilitated, and top clearance is reduced so that properties can be enhanced. For this purpose, as one concrete means for solving the problem, there is provided a high-pressure compressor comprising a compression mechanism for reciprocating/driving a piston with respect to a cylinder by rotation of a motor and compressing an operating fluid sucked by the driving to generate a high-pressure operating fluid. In the high-pressure compressor, the compression mechanism comprises a labyrinth seal structure in which a plurality of labyrinth grooves are formed in a peripheral surface of the piston and no lubrication is performed between the peripheral surface of the piston and an operation inner surface of the cylinder, and a tip end peripheral edge of the piston and an opening end of the labyrinth groove are R-chamfered.
Moreover, according to the present invention, as one concrete means for solving the problem, there is provided a high-pressure compressor comprising a compression mechanism for reciprocating/driving a piston with respect to a cylinder by rotation of a motor and compressing an operating fluid sucked by the driving to generate a high-pressure operating fluid. In the high-pressure compressor, the compression mechanism comprises a labyrinth seal structure in which a plurality of labyrinth grooves are formed in a peripheral surface of the piston and no lubrication is performed between the peripheral surface of the piston and an operation inner surface of the cylinder, and for a relation between the piston and the cylinder, in a top dead point and a lower dead point in the reciprocating/driving of the piston, a tip end peripheral edge and a rear end peripheral edge of the piston are substantially positioned not to enter the operation inner surface of the cylinder.
Furthermore, according to the present invention, as one concrete means for solving the problem, there is provided a high-pressure compressor comprising a compression mechanism for reciprocating/driving a piston with respect to a cylinder by rotation of a motor and compressing an operating fluid sucked by the driving to generate a high-pressure operating fluid. In the high-pressure compressor, the compression mechanism comprises a non-lubricating seal structure between an operation inner surface of the cylinder and the piston, a tip end small diameter portion is formed on the piston, and a small diameter compression section into which the tip end small diameter portion of the piston is inserted when the piston is in a top dead point, and a large diameter portion for forming a compression space in the periphery of the tip end small diameter portion of the piston when the piston is in a lower dead point are continuously formed on the cylinder.
Additionally, according to the present invention, as one concrete means for solving the problem, there is provided a high-pressure compressor comprising a compression mechanism for reciprocating/driving a piston with respect to a cylinder by rotation of a motor and compressing an operating fluid sucked by the driving to generate a high-pressure operating fluid. In the high-pressure compressor, the compression mechanism comprises a non-lubricating seal structure between an operation inner surface of the cylinder and the piston, and the piston is connected to a connecting rod by pressing a connecting flange portion extended to a rear end of the piston in a connection space formed in the connecting rod by a spring so that the piston can oscillate with respect to the connecting rod.
Moreover, according to the present invention, as one concrete means for solving the problem, there is provided a high-pressure compressor comprising a compression mechanism for reciprocating/driving a piston with respect to a cylinder by rotation of a motor and compressing an operating fluid sucked by the driving to generate a high-pressure operating fluid. In the high-pressure compressor, the compression mechanism comprises a non-lubricating seal structure between an operation inner surface of the cylinder and the piston, and a shape of a tip end of the piston and a shape of an inner surface of a cylinder head opposite to the tip end are formed in substantially the same R shape.
Furthermore, according to the present invention, there is provided a compression apparatus, provided with a plurality of stages of compression sections each comprising a cylinder and a piston, for successively passing a gas through the respective compression sections to compress and supply the gas, in which the compression section of the final stage and the compression section of the stage before the final stage are provided with plunger pistons.
Additionally, in the aforementioned invention, a gap in a diametric direction between the cylinder of the compression section of the final stage and the piston reciprocating/operating inside the cylinder is smaller than a gap between the cylinder of the stage before the final stage and the piston reciprocating/operating in the cylinder.
Moreover, in the aforementioned invention, the gap of the diametric direction between the cylinder of the compression section of the stage before the final stage and the piston reciprocating/operating in the cylinder is in a range of 3 to 10 xcexcm.
Furthermore, in the aforementioned invention, the gap of the diametric direction between the cylinder of the compression section of the final stage and the piston reciprocating/operating in the cylinder is in a range of 2 to 8 xcexcm.
Additionally, in the aforementioned invention, the piston reciprocating/operating in the cylinder of the compression section of the stage before the final stage is provided with a plurality of grooves on a surface, and a ratio (B/A) of a groove depth B to a groove width A is in a range of 0.2 to 0.5.
Moreover, in the aforementioned invention, the compression section is constituted of four stages.
Furthermore, according to the present invention, there is provided a compression apparatus comprising a plurality of compression sections. At least one of the compression sections comprises a plunger piston type compressor, the plurality of compression sections are connected in series by a connection pipe, and a compression process of feeding an operating fluid compressed by the compression section of a previous stage to the compression section of a subsequent stage, and compressing the operating fluid in the compression section of the subsequent stage is successively performed to generate the high-pressure operating fluid. In the compression apparatus, a plunger piston in the plunger piston type compressor is sealed by a labyrinth seal constituted by a plurality of labyrinth grooves, the labyrinth grooves are formed so that a forming density decreases to the side of a back pressure chamber from the side of a compression chamber, and a seal property is improved.
Additionally, there is provided a compression apparatus comprising: compression means provided with a plurality of compression sections; driving means for driving the compression means; and a sealed case in which the driving means is disposed and whose top portion closely abuts on the compression means. In the compression apparatus, a relief valve, opened when a pressure in the sealed case is equal to or more than a predetermined pressure, is disposed on a bottom of the sealed case, and worn powder of a movable portion, and the like can be discharged to the outside of the apparatus via the relief valve without disassembling/cleaning the apparatus.
Moreover, according to the present invention, there is provided a compression apparatus in which at least one reciprocating compression section of a plurality of reciprocating compression sections is constituted by a plunger pump, and the plurality of reciprocating compression sections are connected to compress a required gas in multiple stages. In the compression apparatus, the plunger pump comprises a piston inserted into a ceramic cylinder liner, and a connecting rod connected to the piston, a sleeve is interposed as a pressure resistant structure member between the cylinder liner and a plunger pump main body, and the cylinder liner and sleeve are fixed to the plunger pump main body via a fixing bolt.
Furthermore, in the aforementioned invention, elastic cushion members such as a leaf spring are interposed and attached between a connecting rod sleeve into which the connecting rod is inserted and the fixing bolt.
Additionally, in the aforementioned invention, one or two or more pressure release grooves are disposed through a thickness direction in a surface by which the sleeve as the pressure resistant structure member contacts the fixing bolt.
Moreover, in the aforementioned invention, one or two or more pressure release holes are disposed through the connecting rod sleeve.
Furthermore, in the aforementioned invention, a width of either one or both of a piston ring groove and a guide ring groove, disposed in the piston, for attaching a piston ring and a guide ring, is larger than the width of the ring itself.
Additionally, according to the present invention, there is provided a compression apparatus, provided with at least one pair of opposite pistons, a yoke to which the pistons are fixed, and a cross slider for sliding and moving in the yoke, for obtaining a reciprocating motion of the piston from a rotation motion of a crank shaft through conversion by a scotch yoke mechanism, in which a cover provided with an opening in a middle portion not to inhibit a crank pin motion is fixed and disposed to sandwich the yoke.
Moreover, in the aforementioned invention, the cover is shrink-fitted and fixed to the yoke.
Furthermore, according to the present invention, in the aforementioned compression apparatus, a position of at least one pair of opposite positions is provided with no piston, and the position is provided with a connecting rod fixed to the yoke, and a cylinder for guiding the connecting rod so that the connecting rod can reciprocate.
Additionally, according to the present invention, there is provided a compression apparatus, provided with a plurality of reciprocating compression sections, for compressing a gas in multiple stages, in which at least the reciprocating compression section of the first stage is provided with a first compression chamber and a second compression chamber, and a double compression structure of discharging a gas sucked and compressed in the first compression chamber to the second compression chamber and again compressing the gas and subsequently discharging and feeding the gas to the reciprocating compression section of the next stage is disposed.